The primary objective of our proposed research is the precise biochemical elucidation of the structural and functionsal properties of the envelope that enclosed the nucleus of eukaryotic cells. More specifically, we hope to define, in detail, the polypeptide composition of this nuclear envelope and further, to determine which of the several proteins indentified are required to form one of its major constituents, the nuclear pore complex. The approaches proposed to achieve such a characterization involve the preparation of specific immunologic reagents and the development of defined assay systems that will further allow us to study the dynamics of nuclear envelope structure, particularly as pertains to its disassembly and reassembly during mitosis, as well as to formulate experiments directed at understanding the role of the nuclear envelope and pore complex in the regulation of molecular translocation between the nucleaus and cytoplasm. In conjunction with the pursuit of this latter objective, a critical evaluation will be conducted regarding the role of the nuclear envelope, either regulatory or through direct participation, in the crucial biological processes of DNA replication and in the transcription, processing, and transport of the various forms of RNA. So called, "second generation" projects expected to evolve from the results of primary efforts include direct phylogenetic comparisons of the various nuclear envelope components characterized, the elucidation of the structural interactions between the nuclear envelope and its contents, the purification and characterization of any specifically nuclear envelope associated enzyme activities which are identified, and the preparation of homogeneous nuclear envelope proteins in a depolymerized, non-denatured form. Although the proposed research is clearly of a most basic nature, many of its ultimate biomedical ramifications are easily envisioned. The elucidation of the nuclear envelope's role in DNA and RNA metabolism is certain to be crucial to understanding the molecular details of neoplasia and perhaps to the design of rational modes of therapeutic intervention. Similarily, the involvement of the nuclear envelope in such diverse biologic events as eukaryotic viral infection and the cellular response to steroid hormones suggests participation in innumerable pathologic processes.